In electronic packaging, two-dimensional inductors and transformers can be integrated in a top metal layer of the back-end-of-the-line (BEOL) of the package. The inductor or transformer occupies a large area (e.g., 300×300 μm2) in the metal layer, and the inductor has a small inductance value and the transformer has a low efficiency. In addition, the inductor or transformer can have a significant impact on mutual inductance on the package. This impact is due to current passing through the inductor or transformer in a direction parallel to the top and bottom surfaces of the substrate. Thus, the area beneath the inductor or transformer is unoccupied and cannot be used for an active device such as a transistor.
The inductor or transformer also has values that cannot be changed or varied. In other words, the inductance value of the two-dimensional inductor is set during fabrication and cannot be programmed or changed after implementation. Similarly, the two-dimensional transformer cannot be programmed after implementation. Therefore, the package has limited performance and efficiency.
Another drawback to this type of electronic package is when the substrate is made of silicon. The silicon substrate can have losses therein due to eddy currents. In addition, the resonant frequency is low in the silicon substrate.
Because of the disadvantages of the prior art, it would be desirable to provide an electronic package that includes an inductor or transformer that occupies less space and can be programmed to different values based on need after implementation. In addition, it would be desirable for the inductor or transformer to be three-dimensional in which the current passes substantially vertically therethrough to limit the impact of mutual inductance on the rest of the package. The package can also overcome other drawbacks found in the prior art when the substrate is formed of a high-resistance material.